Technical Field
The inventive concept relates to a storage device and a write method thereof.
Discussion of the Related Art
Semiconductor memory devices may be volatile or nonvolatile. A nonvolatile semiconductor memory device can retain data stored therein even when not powered. The nonvolatile memory device may be permanent or reprogrammable. The nonvolatile memory device may be used for user data, program, and microcode storage in a wide variety of applications in the computer, avionics, telecommunications, and consumer electronics industries.
A method of reprogramming memory cells of a reprogrammable nonvolatile memory device may be used to reduce cell coupling. For example, in a reprogramming method, a plurality of program operations is performed to narrow a threshold voltage distribution of data values to be stored. In other words, the reprogramming method may include a coarse program operation and a fine program operation. The coarse program operation may form a rough threshold voltage distribution. The fine program operation may finely narrow a threshold voltage distribution formed by the coarse program operation.
Example reprogramming methods are disclosed in U.S. Pat. Nos. 8,355,280 and 8,411,502 and U.S. Patent Application Publication Nos. 2011/0205817 and 2013/0145234, the disclosures of which are incorporated by reference herein in their entireties.